The exchange took place as Mr Johnson was criticising Labour leader Sir Keir Starmer for repeatedly asking about the crisis in Yemen during today’s Prime Minister’s Questions.
Mr Johnson told the Commons: “We are doing everything we can to support the people of Yemen - given the constraints that we face.
“We’re getting on with a cautious but irreversible roadmap to freedom which I hope that he will support and very shortly Mr Speaker you will be hearing a budget for recovery.”
Sir Lindsay quipped: “I think I already know most of it.”
In an earlier interview with Sky News, the Speaker slammed Mr Sunak’s pre-Budget PR drive, saying that policies should be announced to MPs first because “tradition matters”.
He said it is “important that people hear it on the floor of the House” first and suggested that approach is something “we’ve got to get back to”.